Joint of single steel pipe beam and truss-column is widely adopted in substation design.But there is no clear method for its calculation.So the research of the joint can help us make the calculation easily.ANSYS is used to make finite element analysis of the joint.A typical case is applied to the joint;and then the displacements and stresses of the joint are discussed.Some rules for joint calculation are given.According to the displacements and stresses of joint,a calculating method of the joint is given by referencing the formula of rigid flange.